The present invention relates generally to the field of construction layout. In particular, the present invention relates to a method for locating wall lines during construction layout, and an apparatus for use in locating the wall lines.
When a new building is constructed, a floor plan is generated electronically with the use of a drafting program. The floor plan is a scaled, sectioned, top view of the building as it will appear on the site. Typically, the floor plan includes predetermined defined lines and other relevant details defining the walls that are to be located on the site, the lines and relevant details assist a contractor in laying out the building at full size on the construction site. The process of reading the plan details and converting the defined lines from the scaled floor plan to full size on the construction site is typically referred to as construction layout.
During construction layout, wall lines must be accurately located on the site. One method involves the use of a builder's level and a tape measure and a blueprint plan with dimension lines and detail references between lines to establish the lines on the site. During construction layout, a line is chosen that will be used as the reference line for the layout of other wall lines. Because the scaled relationship between wall lines is known from the floor plan, the full-scale relationship between the wall lines is also known. A second wall line is marked by measuring a known distance in a known direction from the reference line. Subsequent wall lines are established by marking points near each end of a wall line, each mark is then connected to a mark on an opposite end of a wall line, creating a fully defined wall line in full scale between the two marks. Laying out marks for lines by reading and transferring references from blueprints with handheld tools is a time consuming practice that requires a significant amount of expertise and typically requires at least two people.
Electronic surveying equipment, such as a total station, provides an attractive alternative to manual construction layout. A total station is an electronic transit and electronic distance measuring device that can accurately determine angles and distances from the total station. A transit is a precision instrument used for measuring angles in the horizontal and vertical planes. To determine distance, a laser is beamed from the total station to a reflective prism, mounted near the top of a prism stake, and the electronic surveying equipment measures the amount of time the light takes to reflect back to the total station from the prism. When utilizing a prism stake, the prism stake has a point at its base, and the point is set at a particular location to allow the total station to provide an accurate reading. The prism may also be manually mounted and leveled on a tripod or other similar device. To ensure an accurate reading, the prism must be completely level above the point that is being located, because any lean from the vertical will provide an inaccurate reading due to the prism being slightly offset from the point that is being marked. Alternative, a laser-light may be projected downward from a tripod that the prism is mounted on, and the laser-light will indicate the point over which the prism is located. The total station conveys the coordinates of the point to the user via a handheld unit is also used to control the total station.
In construction layout utilizing a total station, the floor plan must be converted into defined points and the defined points uploaded to the total station. On the construction site, the user selects a predetermined point associated with the wall that the user is attempting to mark and communicates this information to the total station. The user levels the prism stake at a point on the construction site, which point will serve as a reference point for the total station. The total station locates the prism and informs the user, almost instantly on the handheld unit, of the distance from the prism stake to the selected defined point that the user created and is marking. For example, the total station will inform the user that the defined point is located 15 inches west and 7 inches north of the prism. The user then takes that information and moves the prism stake from the reference point established by the prism to the defined point, as indicated by the total station, and continues this process until the point is accurately located and marked.
Even when using a total station, construction layout is a time consuming process requiring a significant amount of expertise. Initially, the floor plan is converted into points, which may consist of hundreds or thousands of points generated on and defining the floor plan. The points created are generally surveying points, which indicate a precise location on the site. Each point is located and marked using a prism mounted on a rod or tripod. The prism must be sufficiently level whenever the user attempts to mark the point, to ensure that the distance calculated from the total station to the prism accurately conveys the distance from the total station to the point.
While hundreds or thousands of points are generated, each point has a general description, for example “100” for the one hundredth point. Such a general description fails to convey the necessary information needed to perform construction layout, such as the location of and orientation of walls. Additionally, each of the hundreds or thousands of points may have differing purposes depending on the construction layout, which leads to a loss of efficiency experienced by the user. The hundreds or thousands of points may represent a location of the centerline of a wall, the edge of a wall, the intersection between walls, or another relevant location. Yet the data provided by current plan converting methods for the surveying equipment merely gathers information for locating actual surveying points and fails to provide and communicate the purpose or features of that point. Thus, there exists a need for an improved method of construction layout. There also exists a need for an apparatus for use with the method of construction layout.